So let me get this straight…

I know this question has been asked so much that I'm sure most of you have probably been annoyed by now, but id appreciate if someone could at least explain it to me like if I was a kid, cause I'm still a bit confused. So from what I understand, we have until the end of this month to pick a plan, and if we don't they'll pick one for us, but the part that confuses me the most is the placeholder part, because I checked my account (Nelnet) and I says I don't have to pay until the 2028, which is something Ive been noticing in other posts as well, thanks in advance…